Whereas Perspective Drawing is the art of recreating three-dimensional objects on a single plane (flat) drawing, the use of vanishing points, for each surface plane of the object, is necessary to give the appearance of depth.
In viewing a scene, lines on plane surfaces appear to converge at a point on the horizon, which is the meeting line of the sky and ground. For objects of extreme height, or with multiple surfaces at oblique angles to one another, additional vanishing points exist, other than those on the horizon. In each case, every vanishing point must be plotted, once its existence is determined to be necessary.
In perspective drawing, there are direct relationships between drawing size and distance between vanishing points. Architects, engineers, draftsmen and others who use perspective drawing, usually desire the drawing to be as large as possible to exact maximum detail. Big office complexes and huge buildings and other large objects can require drawings up to 3 foot by 5 foot to include all the required architectural and engineering detail.
As the drawing gets larger, the vanishing points get farther away; sometimes requiring vanishing point distances of 5 to 10 feet away from the actual drawing paper. This represents a real problem to the person making the perspective drawing as he must stretch a string or ruler these distances to get accurate perspective lines. Also, he must have a large drawing surface on which to place these vanishing points.
Many inventions and methods have been disclosed to solve this problem. In each disclosure, the limitations are obvious and these limitations restrict the usefulness of the invention. For example, some inventions require the use of a complicated and cumbersome apparatus. Others only offer very limited vanishing point distances. Still others require estimating of perspective lines not included in the embodiment of the invention or method.
It is the object of this invention to provide a means to enable anyone to make a perspective drawing of any size suitable to the needs presented by the object being drawn.
Another object of the invention is to provide a means to restrict to the drawing paper any and all vanishing points, or vanishing point references.
Another object of this invention is to provide a means to enable anyone to construct a perspective drawing which conforms to all popular and recommended procedures, sizes, relationships and laws for perspective drawing, with as many vanishing points as are necessary and from any viewpoint desired, with the provision included that all perspective lines that must appear in the drawing can be constructed through the use of this invention.